ABSTRACT
Microscopy is among the oldest and still the most scientically important applications of optics with a rich heritage extending hundreds of years. The fundamental physical principles of microscopy were established by Rayleigh, Abbe, and others around the end of the nineteenth century (Born and Wolf 1999). The diffraction limit of approximately one wavelength was established, but as we will see in the following, this is not a simple limit and care must be exercised in its interpretation. Notwithstanding this centuries-old heritage, there are an increasing number of exciting developments in the microscopy of both illuminated (e.g., sensitive to spatial variations in the complex index of refraction) and self-luminous (uorescent/ photoluminescent) objects. Indeed, we are on the verge of enormous breakthroughs in microscopy and ultimately nanoscopy that will extend microscopy’s reign as the most important scientic application of optics well into the future and will provide useful competition to other imaging modalities such as electron-beam microscopy and the many variants of atomic force/ scanning tunneling microscopy.
